JavaScript: Find the greatest common divisor of two positive numbers

JavaScript Function: Exercise-2 with Solution

GCD Using Recursion

Write a JavaScript program to find the greatest common divisor (GCD) of two positive numbers using recursion.

Visual Presentation:

Sample Solution-1:

JavaScript Code:

// Function to calculate the greatest common divisor (GCD) of two numbers using Euclidean algorithm.
var gcd = function(a, b) {
    // Base case: if b is 0, then GCD is a.
    if (!b) {
        return a;
    }

    // Recursive case: calculate GCD using the remainder (a % b).
    return gcd(b, a % b);
};

// Example usage: Calculate and print the GCD of 2154 and 458.
console.log(gcd(2154, 458)); 

Output:

2

Flowchart:

Live Demo:

See the Pen javascript-recursion-function-exercise-2 by w3resource (@w3resource) on CodePen.

Sample Solution-2:

JavaScript Code:

// Function to calculate the GCD of two numbers using recursion.
function gcdRecursive(a, b) {
    // Ensure both numbers are positive.
    a = Math.abs(a);
    b = Math.abs(b);

    // Base case: if one of the numbers is 0, the other number is the GCD.
    if (b === 0) {
        return a;
    }

    // Recursive case: calculate GCD using the remainder (a % b).
    return gcdRecursive(b, a % b);
}

// Example usage: Calculate and print the GCD of 2154 and 458.
console.log(gcdRecursive(2154, 458));

Output:

2

Flowchart:

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